History: The MSL rover Curiosity observed a very small rock informally named Egg Rock (Henceforth Aeolis Mons 001), on sol 1505. The rock was about 2.5 m from the rover, which was close enough to interrogate with Mastcam and ChemCam (LIBS chemical analysis and RMI). Aeolis Mons 001 is small (4-5 cm) rounded, and apparently hemispherical. It was seen only from one side. Another small fragment in the same rover location appears in MastCam imagery, identified by multispectral analysis (Wellington et al., 2017) but was not further investigated.

Physical characteristics: Aeolis Mons 001 has a lustrous blue-gray color and contains oval shaped depressions consistent with regmaglypts as well as elongated hollows that could result from ablation during entry or in situ differential erosion of less-resistant inclusions. At high resolution, the surface is smooth. The mass of the meteorite is estimated to be ~250 g.

Geochemistry: Mastcam color images reveal the presence of subtle surface patches on the surface, consistent with ferric materials, while other regions have reflectance spectra consistent with laboratory spectra of fresh iron meteorites (Johnson et al. 2016, Wellington et al. 2017). Chemistry and mineralogy consistent with iron meteorites are inferred from ChemCam analyses. Aeolis Mons 001 was interrogated using a 3x3 ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) raster with accompanying Remote Micro-Imager (RMI) images. The ChemCam elemental spectra show both iron and nickel peaks at all nine points (Meslin et al., 2017). Comparison of these spectra with spectra measured on several iron meteorites with a replica of ChemCam in the laboratory at the Institut de Recherche en Astrophysique et Planétologie (IRAP) indicate that Aeolis Mons 001 is mostly made of kamacite and contains ~8 wt. % Ni. One point (#9) along the edge of an elongated cavity also exhibits P peaks and is enriched in Ni (Fig. 3). The colocation of Fe, Ni, and P in point #9 suggests the presence of schreibersite, (Fe,Ni)3P on the rim of this cavity.